Re: [v6ops] SLAAC renum: Problem Statement & Operational workarounds

Fernando Gont <> Fri, 25 October 2019 17:34 UTC

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To: Ole Troan <>, "Eric Vyncke (evyncke)" <>
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From: Fernando Gont <>
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Subject: Re: [v6ops] SLAAC renum: Problem Statement & Operational workarounds
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On 24/10/19 10:38, Ole Troan wrote:
> Eric,
>> What about a "IPv6 renumbering considered harmful" or "Unstable DHCP-PD prefix considered harmful" ?
> Perhaps, but isn't there a long list of documents the IETF has produced on IPV6 renumbering already?
> Would a new document say anything new and more useful?
> And it's not like DHCPv6 PD (RFC3633) isn't clear either. From the abstract:
>    The Prefix Delegation options provide a mechanism for automated
>    delegation of IPv6 prefixes using the Dynamic Host Configuration
>    Protocol (DHCP).  This mechanism is intended for delegating a long-
>    lived prefix from a delegating router to a requesting router, across
>    an administrative boundary, where the delegating router does not
>    require knowledge about the topology of the links in the network to
>    which the prefixes will be assigned.

Long-lived != immortal. As long as a prefix eventually changes, that is
when the problem may be experienced.

> That said, if people want to write a "IPv6 networks need stable prefixes" document, go ahead.
> I'm skeptical that playing with prefix timers and protocol mechanisms will do more than put lipstick on the pig.

It's not putting lipstick on a pig. In the current situation, hosts
essentially do not react to prefixes that fade away. This is something
that can be easily improved.

> Iff we wanted to solve ephemeral addressing / connectivity, that's would require something else.

Could you please elaborate on what you mean by ephemeral addressing /

Fernando Gont
SI6 Networks
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